package com.hm.common.util;

import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * 以静态变量保存Spring ApplicationContext, 可在任何代码任何地方任何时候中取出ApplicaitonContext.
 */
@SuppressWarnings("unchecked")
public class SpringUtil implements ApplicationContextAware {
	private static ApplicationContext context;

	/**
	 * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量.
	 */
	public void setApplicationContext(ApplicationContext context) {
		SpringUtil.context = context;
	}

	/**
	 * 取得存储在静态变量中的ApplicationContext.
	 */
	public static ApplicationContext getApplicationContext() {
		checkApplicationContext();
		return context;
	}

	/**
	 * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
	 */
	public static <T> T getBean(String name) {
		checkApplicationContext();
		return (T) context.getBean(name);
	}

	/**
	 * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
	 */
	public static <T> T getBean(Class<T> clazz) {
		checkApplicationContext();
		return (T) context.getBean(clazz);
	}

	/**
	 * 清除applicationContext静态变量.
	 */
	public static void cleanApplicationContext() {
		context = null;
	}

	private static void checkApplicationContext() {
		if (context == null) {
			context = new ClassPathXmlApplicationContext("spring/system.xml");
		}
	}
}